A flute headjoint is that portion of a flute or piccolo consisting of a length of tube which is closed at one end and attachable to the main body of the flute at the other end. A lip plate having a lip plate aperture or embouchure hole is mounted on the side of the headjoint tube via a short length of tube, called a chimney, extending between the underside of the lip plate and the side of the headjoint tube. The headjoint tube has an aperture in the side wall thereof which is aligned with the chimney bore and the lip plate aperture so as to form an air passageway between the lip plate aperture and the interior of the headjoint tube.
The lip plate of a conventional flute headjoint comprises a front portion located in front of the lip plate aperture, and a rear portion located behind the lip plate aperture and a downward extension of the lip plate called a skirt located along the edges of the lip plate. The flute player positions his lips on the front portion of the lip plate. The rear edge of the lip plate aperture and the rear inside wall of the chimney form an embouchure wall located opposite the flute player's lips. When a flute player plays the flute, the flute player blows a stream of air across the top surface of the lip plate aperture. The top edge of the embouchure wall divides the stream of air from the flute players lips into a primary air stream which travels into the body of the flute headjoint, and a secondary stream which passes across the rear portion of the lip plate. In a conventional flute, the secondary air stream travels across the rear portion of the lip plate in a fan-like pattern. This dispersion of the secondary air stream limits the sound volume produced by the flute and imparts certain undesirable tonal qualities to flute play.
Throughout history, the lip plates of flutes have undergone design modifications aimed at improving flute play. Some lip plates have been modified so as to adjust the positioning of a flute player's lips. Such modified lip plates involve changes to the front portion of the lip plate which often results in flute headjoints having restricted playing characteristics. These flute headjoints often have embouchure walls which are positioned higher relative to the flute player's lips as compared to ordinary headjoints, which produce peculiar tonal qualities and restricted playing characteristics.
Pompetzki (German Pat. No. 2407754) discloses a flute headjoint having a variable lip aperture. The Pompetzki headjoint uses a movable member mounted within the lip plate for opening or closing the lip plate aperture as desired. The Pompetzki headjoint does not change the path of the secondary air stream and, therefore, must suffer from the same drawbacks as other conventional flute headjoints.